Facebook annoyed and puzzled many people last year when it forced them to download its Messenger app for chats. Its reasons for doing so are now clearer: Messenger is becoming a beast of an app, with its own links to outside businesses and software apart from Facebook’s main site.

At the company’s F8 developer conference this week in San Francisco, executives pulled back the curtain on the new Messenger. It’s now a storefront and a platform for other mobile apps, which can be downloaded from within Messenger and integrated into people’s Messenger chats. There are more than 40 outside app partners already aiming to spice up users’ conversations with things like personalized GIFs, tools to turn your texts into songs, and even sports animations from ESPN. The apps can be accessed by hitting the “...” button on the Messenger compose screen.

Users can still send each other plain old text-based messages. But why do that when the Messenger app Ditty can turn your text into a song? Or when you can superimpose fire onto your friend’s house with Pyro?

These sorts of integrations, Facebook CEO Mark Zuckerberg said at F8, are meant to give people more tools to express themselves and say what they want to say better.

Also, Facebook is now positioning Messenger as a business platform. Soon, when people buy things from select online retailers, they’ll be able to sign up for updates like shipping notifications from within Messenger, or chat with the retailer there, or even change their order. Facebook thinks this is better than having to use regular email or phone calls to engage with the business. Facebook’s initial retailer partners include Zulily and Everlane.

Plus, Messenger users now have the ability to send each other money. You can’t buy things from businesses directly through Messenger yet, but it’s not hard to imagine Facebook going down this route, especially as the company experiments with a “buy button” on Facebook’s main site.

Meanwhile, Facebook Messenger handles quite a few voice calls. In fact, it accounts for more than 10 percent of mobile VoIP calls globally, Zuckerberg said.

Messenger now has roughly 600 million users who log in at least monthly, Zuckerberg said. That’s almost half the size of Facebook’s total user base.

Late last year, at a public Q&A, Zuckerberg said Facebook split Messenger off to make it a better, faster messaging product. Apparently, Facebook also thinks Messenger can do a lot of other things better.